Sacro-Iliac Joint Dysfunction
Sacroiliac joint dysfunction or incompetence generally refers to pain in the sacroiliac joint region that is caused by abnormal motion in the sacroiliac joint, either too much motion or too little motion. It typically results in inflammation of the sacroiliac joint, and can be debilitating. While it is not clear how the pain is caused, it is thought that an alteration in the normal joint motion may be the culprit that causes sacroiliac pain. The source of pain can be either:
Too much movement (hypermobility or instability): The pain is typically felt in the lower back and/or hip and may radiate into groin area.
Too little movement (hypomobility or fixation): The pain is typically felt on one side of the low back or buttocks, and can radiate down the leg. The pain usually remains above the knee, but at times pain can extend to the ankle or foot.
The pain is similar to sciatica, or pain that radiates down the sciatic nerve and is caused by aradiculopathy.